Coastal Coastal ProcessesProcesses

November 17November 17

Edge WavesEdge Waves produced by the variability of wave energy produced by the variability of wave energy

reaching shore. reaching shore. Waves tend to come in groups, especially when Waves tend to come in groups, especially when

waves come from distant storms. For several waves come from distant storms. For several minutes breakers may be smaller than average, minutes breakers may be smaller than average, then a few very large waves will break. then a few very large waves will break.

The minute-to-minute variation in the height of The minute-to-minute variation in the height of breakers produces low-frequency variability in the breakers produces low-frequency variability in the along-shore current. This drives a low-frequency along-shore current. This drives a low-frequency wave attached to the beach, an edge wave. wave attached to the beach, an edge wave.

The waves have periods of a few minutes, a long-The waves have periods of a few minutes, a long-shore wave-length of around a kilometer, and an shore wave-length of around a kilometer, and an amplitude that decays exponentially offshore amplitude that decays exponentially offshore From Stewart

Figure 17.6 in Stewart. Computer-assisted sketch of an edge wave. Such waves exist in the breaker zone near the beach and on the continental shelf. From Cutchin and Smith (1973).

Coastal ProcessesCoastal Processes

Wide range of influences – Wide range of influences – generalizations are difficultgeneralizations are difficult

As water gets shallower, frictional As water gets shallower, frictional processes become more importantprocesses become more important

In water <50 m deep, bottom and In water <50 m deep, bottom and top Ekman layers mergetop Ekman layers merge

Non-linearity may be importantNon-linearity may be important

Coastal ProcessesCoastal Processes

Bottom slope/bathymetry is a major Bottom slope/bathymetry is a major influenceinfluence

Time-dependence in winds – direct Time-dependence in winds – direct response of currents response of currents

Fresh water input – must be Fresh water input – must be transported across shelftransported across shelf

Coastal trapped wavesCoastal trapped waves

Already saw Kelvin and edge wavesAlready saw Kelvin and edge waves Continental Shelf Waves exist because of Continental Shelf Waves exist because of

sloping bottom – also called Topographic sloping bottom – also called Topographic Rossby Waves Conserve Potential Rossby Waves Conserve Potential Vorticity:Vorticity:

but h changes due to sloping bottombut h changes due to sloping bottom Propagate with shallower water – coast to Propagate with shallower water – coast to

the right in Northern hemispherethe right in Northern hemisphere

h

f

ω1 ω2

h1 h2

2

2

1

1

hh

h1 h2 h3

coast

Winds to south of Tampa cause changes here – coastal response atEgmont is integrated effect of winds blowing to the south – all the way to the Keys

Continental Shelf Wave phase speed is given by:

Where is bottom slope, g is acceleration of gravity, f is the Coriolis parameter, R is the Rossby Radius of Deformation, and kx and ky are the cross-shelf and along-shore wave numbersFor the West Florida Shelf, c = 8.2 m/s (Mitchum and Clarke, 1986)Hurricane Dennis moved up the shelf at 8.3 m/s

Hurricane Dennis made landfall near Pensacola, FL late on July 10, 2005. Unexpected storm surge occurred 140 miles away in Apalachee Bay and was recorded by the COMPS water level system at Shell Point.

Hurricane Dennis forced Continental Shelf Wave up the coast, leading to much higher storm surge at Shell Point than predicted

COMPS water level record, SLOSH Gulf-wide model water level, and tidal prediction from Shell Point, FL, for Hurricane Dennis.

SLOSH has been re-configured based on these observations

Modeled water level from Morey, et al. (2006) for Shell Point, FL for Gulf-wide model, NE Gulf model, and local (nested) model

Similar forced CSW lead to major flooding Similar forced CSW lead to major flooding in the Tampa Bay area during Tropical in the Tampa Bay area during Tropical Storm Josephine in 1996Storm Josephine in 1996

To predict Tampa Bay, must predict W. To predict Tampa Bay, must predict W. Fla. ShelfFla. Shelf

Influence of boundary currents – filaments, Influence of boundary currents – filaments, meanders – “wiggles” in Gulf Stream or meanders – “wiggles” in Gulf Stream or Loop Current can inject nutrients onto Loop Current can inject nutrients onto shelf, transport biogenic properties, etc.shelf, transport biogenic properties, etc.

VERY nearshore processes – sediment VERY nearshore processes – sediment transport in surf zone, etc.transport in surf zone, etc.

The US Integrated Ocean Observing System and the Gulf of Mexico

Mark E. LutherCollege of Marine ScienceUniversity of South Florida

US-GOOS Steering Committee

IOOS: The US Contribution to GOOSIOOS: The US Contribution to GOOS1 System, 7 Goals1 System, 7 Goals

Locally Relevant – Nationally CoordinatedLocally Relevant – Nationally CoordinatedBenefits Many User GroupsBenefits Many User Groups

Improve the safety & efficiency of marine operationsImprove the safety & efficiency of marine operations Improve homeland securityImprove homeland security Mitigate effects of natural hazards more effectivelyMitigate effects of natural hazards more effectively Improve predictions of climate change & their Improve predictions of climate change & their

effectseffects Minimize public health risksMinimize public health risks Protect & restore healthy coastal marine ecosystemsProtect & restore healthy coastal marine ecosystems Sustain living marine resourcesSustain living marine resources

Ultimate goal of IOOS is to provide useful products for anyone who makes decisions in coastal regions of the US - see http://ocean.us

Architecture

NORLC 2

U.S. IOOSThree Scales of Observations

NationalBackbone

Global Ocean Climate Component

GOOS/GCOS Coastal Ocean

GLs NE

MAB

SEGoMex

HIsl

GoA

NW

SW

RegionalObservingSystems

Integrated, Multi-Scale Integrated, End-To End

NORLC 4

Analysis, Modeling

Data Communications & Management

MonitoringIn Situ & Remote Sensing

Groups that Use, Depend on, Manage or Study Oceans & Coasts

IOOS

EndToEnd

Data &Information

AssessImprove

Real-time Obs from GTS Feb 2005

Surface Obs – Drifters, Moorings

Subsurface Obs – XBTs, Argo, Moorings

Global Component of the Observing SubsystemIntegrate Remote & In Situ Sensing

An International Collaboration

Coastal Component – A Coastal Component – A System of Systems System of Systems ApproachApproach

• Provides data & info required by regions• Reference & sentinel station-network• Data standards & exchange protocols• Operated by NOPP Agencies & RAs

• Designed & operated by Regional Associations

• Involve user groups in design & evaluation of the IOOS

• Resolution Variables Based on user needs for data & information

Regional COOS’s

National Backbone

Ultimate goal of IOOS is to provide useful products for anyone who makes decisions in coastal regions of the US - see http://ocean.us

Observing Systems in Florida are building blocks of both the Southeast Atlantic Coastal Ocean Observation Regional Association (SECOORA)/Southeast Atlantic Coastal Ocean Observing System (SEACOOS) and the Gulf of Mexico Coastal Ocean Observing System (GCOOS) – see www.seacoos.org and www.gcoos.org

SEACOOS

GCOOS Activities

Formally established by Memorandum of Agreement in January 2005 – At present, there are 41 signatories to the MOA

Board of Directors Elected in June 2005

Board meets Aug. 25-26 in Houston

Business Plan drafted and will be refined/approved by Board

Workshop for Oil and Gas Production and related industries Nov. 2-4 in New Orleans

IOOS and Public Health Workshop Jan. 23-25 in St. Petersburg

GCOOS Board of Directors:

Private Sector representatives   Cortis Cooper, ChevronTexacoAlfred Prelat, The Boeing CompanyRaymond Toll, Science Applications International Corporation Jan van Smirren, Fugro GEOS   Governmental representatives    Robert (Buzz) Martin, Texas General Land OfficeChris Oynes, Minerals Management ServiceDon Roman, University of Southern Mississippi

Academic representatives    Mark Luther, University of South Florida Worth Nowlin, Texas A&M UniversityNancy Rabalais, Louisiana Universities Marine Consortium Education and Outreach representatives   Mike Spranger, Florida Sea Grant ProgramSharon Walker, J.L. Scott Marine Education Center & Aquarium